Remote control system



Dec. 14, 1937.

F. M. HARRIS REMOTE' CONTROL SYSTEM Filed July l5, 1933 124 Sheets-Sheet l I IIIIIII'IIITII Dec. 14, 1937. F. M, HARRis REMOTE CONTROL SYS TEM Filed July l5, 1933 2 Sheets-Sheet 2 INVENTOR.

Patented Dec. 14, 1937 UNITED STTES iATET FFECE 17 Claims.

My invention relates to remote control systems and particularly to a system for the remote con trol of a radio receiver by means ci which a desired preselected radio station may be tuned in from a remote point.

One of the objects of my invention is to provide a remote control system or" the above-mentioned type which is low in cost and satisfactory in operation.

A further object of my invention is to provide a remote control tuning system which is operated merely by the closing of a relay through a single remote control circuit whereby the system is simple and positive in operation.

A still further object ci my invention is to provide a remote control system of the abovementioned type in which the stations to be tuned in by remote control may easily be preselected by the owner of the radio receiver.

In practicing my invention l provide a relay at the radio receiver which, response to the closing oi a remote control circuit, connects a motor to a source of power for rotating the tuning condensers. A holding circuit is provided for the relay so that, once the relay is closed, it remains closed until the holding circuit is broken. Means is provided for breaking the holding circuit when the tuning condenser has been rotated to the desired point and for returning the holding circuit to its closed condition whereby the next station may be tuned in by again closing the remote control circuit.

Other features and advantages of my invention will appear from the following description taken in connection with the accompanying drawings, in which Figure 1 is a schematic and circuit diagram showing an embodiment of my invention;

Fig. 2 is a View taken on the line II-II of Fig. l;

Fig. 3 is a schematic and circuit diagram of another embodiment oi my invention;

Fig. 4 is a view taken on the line IV-IV of Fig. 3;

Fig. 5 is a detail View of one of the cam arms shown in Figs. 3 and 4;

Fig. 6 is a cross-sectional view taken on the line VI-VI of Fig. 5;

Fig. 7 is a schematic diagram of another embodiment of my invention;

Fig. 8 is a View taken on the line VIII-VIII of Fig. '7, and

Fig. 9 is an end View of the variable condenser and short-circuiting switch shown in Fig. 7.

(Ci. Z50-d0) Fig. 1G is a side view and a circuit diagram of another embodiment of my invention, and

Fig. il is an end view of a portion of the structure shown in Fig. 10.

Referring to Fig. i, the tuning condenser, which 5 is oi' conventional construction, is indicated at I. The rotor shaft il or the condenser i is connected to an alternating current motor 5 through reversing mechanism l.

Tie motor E is connecte-d to a power source 9 means ci a relay li when the relay is closed.

The relay i comprises an armature i3 of conducting material to which are fastened two magnetic cores and A relay winding is surrounds the core i5, the lower end or" this winding being connected to one terminal of the power source t through a conductor 2i. The upper end the winding it is connected through a cable conductor 2S to one terminal of a switch 25. The other switch terminal 2l is connected hrough a second cable conductor 2S to the other terminal of the power source 9.

All of the apparatus at the right ci the broken line is located at the radio receiver while the switch 25 at the left of the line 3i is located at the remote control point, the switch being connected to the radio receiver by a cable having only the two conductors 23 and 29.

It will be seen that when the switch 25 is closed, a circuit is completed through the relay winding and the armature i3 is pulled up into contact with contact points 33 and 35. This connects the motor 5 across the power source 6 and the motor begins to turn the rotor of the tuning condenser i.

When the armature i3 is pulled up it also closes a holding circuit through a relay winding 3l which surrounds the core il. The holding circuit may be traced from the leit-hand terminal ci the power source through a conductor 3Q, the relay winding a relay contact point Iii, the armature and core il' through a conductor to a switch contact point and through a spring switch arm and a conductor fl@ to the right-hand terminal of the power source 9.

The motor 5 having been started by closing the switch momentarily, it continues to run and rotate the tuning condenser i until the holding circuit is broken at the contact point 'Ihe mechanism for breaking the holding circuit and for setting the tuning condenser i exactly at the proper position for receiving a desired station includes a disc 5i fastened to the shaft 2 to rotate with the rotor of the condenser I. As indicated in Figs. 1 and 2, circular depressions' are drilled or otherwise formed in the face of the disc i, each depression being located in the proper position to stop the condenser rotor at the desired station setting.

A spring arm 55 which carries a ball bearing 57 held in a retainer 59Vis mounted near the edge of the disc 5! with the ball 57 so placed that, as

the disc El is rotated, the ball 57 seats itself successively in the depressions 53.

The end of the spring arm 55 has a projection Si thereon so placed with respect to the switch arm 47 that, when the ball 57 is seated in a depression 53, the projection 6l is underneath Vthe switch arm 47 as illustrated. When the disc 5i is rotated so that the ball 57 rides up out oi the depression, the projection El is moved to the right against the switch arm 7 and past it, the switch arm il being short enough to permit the projection to slide past. The projection is now on the right-hand side of thespring arm 437, and, when the disc 5i rotates to a point where the ball 57 seats itself in the next depression 53, the projection 6i will move to the left and break the holding circuit as it again slides past the switch arm t7. The projection 5i is now in its original position on the left-hand side of the switch arm Q7 as shown in Fig. l.

Since the conventional type of tuning condenser is varied from its minimum to its lmaximum capacity when rotated through 180 degrees, it may be desirable to employ a mechanism vfor automatically reversing the direction of rotation of the condenser when it reaches the positions of maximum andV minimum capacity.

The reversing mechanism illustrated in Fig, 1 comprises gear wheels 63 and S5 rotatably mounted upon the shaft 3. The' gear wheel 63 is continually in Vmesh with a gear wheel 67 keyed to the'motor shaft B9 while the gear wheel 65 is always connected to the other gear wheel 7i keyed to the shaft t9 through the gear wheels 73 and 75 on thecounter shaft 77.

The gear wheels are caused to rotate the shaft 3 by means of a circular member 79 slidably mounted upon the shaft 3 and secured in nonrotatable relation therewith by means of a spline 8l. A dog 83 projects from the left side of the member 79 for engagement with asdepressionin the side of the gear wheel 63 when the member 79 is moved to the left to the position illustrated. In this position the gear wheel 63 drives the shaft 3 through the member 79.

Another-dog 85 projects from therright side of the member 7@ for engagement with a depression in the side of the gear wheel S5 when the memberV 75 is moved to the right. When in this position, the shaft 3 is driven by the gear wheel 55.

The member 7 is moved Vto the right or left by means of a horizontal rod 87 slidably supported in supporting members 39 and 9i. A vertical arm 93 is pivotably fastened to a supporting member 95 and pivotably secured to the horizontal rod '37. The lower end of the arm S3 extends Yinto a circular groove 96 in the member 7s whereby the dogs 83 and 85 are moved to the right when the rod 87 is moved to the left, and to the left when the rod 87 is moved to the right.

A spring biasing device is provided for holding the member 79 in either its right-hand or lefthand position, depending upon the direction in which the member 79 is kicked by the arm 93. The biasing device comprises an arm 9S extending into the groove 96 and pivotally mounted at its lower end upon a suitable support IDI. A biasing spring w3 is fastened at its upper end to the arm 99 and at its lower end to the support mi at a point underneath the arm Vpivot point whereby the arm 99 will be pulled to either the right or Vthe left of thevertical position depending upon the direction of the kick given the member 79.

The automaticV operation of the reversing mechanism is accomplished by means of a semispherical projection 455 on the back of the plate 5i and a depression H37 in the back of the plate almost diametrically opposite projection lil.`

The right end of the rod 87 carries a contact member m9 which is held against the plate 5I at all times by means of a spring il i.

It will be understood from the foregoing description that when the projection I rotates past the contact member IGS, the member 79 isY kicked over to the right and held there by the biasing arm S9 so that the condenser i is rotated in the opposite direction by the gear wheel 65. The direction of rotation of the plate i is also reversed and, while this reversal causes the rod 87 to be moved to the left again by the projection B95 as it begins its rotation in the reverse direction, there Vis no eifect produced since the member 79 is being held over to the right by the spring biasing device. The member 79 is held over to the right far enough so that when the Varm 93 is given Vthe second kick it does not come in contact with the member 79.

When the depression |07 rotates past the contact member tot, the spring il! forces the rod to the right whereby the member 79 is kicked over to the left, the biasing arm 99 being kicked over to its left-hand position at the same time, and the direction of rotation of the condenser Yl is again reversed. As before, the second kick given to the arm 93 will have no effect as the arm 93 will not come into contact with the member 79. Y

By means of my improved apparatus any diiiiculty due to over-running of the motor 5 and the consequent mistuning may be avoided. With this in mind, the preferred adjustment of the projection iii with respect to the spring switch arm 37 is such that the holding circuit is broken as the ball 57 is seating itself in a depression Y 53. If the inertia of the rotating parts (the the action of the ball 57 will, in part be that of a brake after it has become seated.

Under the conditions assumed, however, there is more than a braking action because the spring 55 is made stiff enough so that it and the ball bearing 57 can actually rotate the plate 5| a slightV amount. That is, if the over-run of the motor 5 is too great, the ball 57 will seat itself in a depression 53 and then; acting as a brake, ride part way out of the depression. YHere rotation of the plate 5i is stopped for an instant and then the force of the spring 55 again seats the ball, the Vrotation of the plate `Siebeing reversed to accomplish this. Thus, in the example assumed, the spring 55 reverses the direction of rotation of the condenserrotor to set the condenser at the exact position required to receive a desired station.

If the inertia of the rotating parts is small, the motor 5t will stop driving the plate 5| before the'ballvl has became seated, this being the preferred adjustment. In this case, the force of the spring 55 seats the ball in a depression 53, the spring 55 driving the plate 5l, after the holding circuit is broken, in the same direction in which the motor was driving it.

When employing the last-mentioned adjustvment, it may be desirable to connect the gear wheels 61 and 1| to the motor shaft 69 through one-way clutch mechanisms, of any suitable construction, in order that, when the spring drives the plate 5|, it will not have to rotate the motor armature.

In the embodiment of my invention illustrated in Fig. 3, provision is made for more easily presetting the radio receiver for any desired group of stations than is permitted by the design shown in Fig. 1.

Referring to Fig. 3, where like parts are indicated by the same reference numerals as in Fig. 1, the rotor of the tuning condenser is always driven in the same direction through a gear wheel H3 which is keyed to the shaft 3 and which engages a pinion H4 on the motor shaft. The means for breaking the holding circuit at the desired instant includes a plate H5 keyed to the shaft 3 so that it rotates with the rotor of the condenser In place of depressions 53 drilled in the face of the plate, as in Fig. 1, station selecting or cam arms H1 are provided, there being one selecting arm for each station to be selected.

The structure of the selecting arms |1 will be better understood by referring to Figs. 5 and 6. Each arm H1 comprises a metal bar H9 which is trapezoidal in cross-section for a portion of its length. One end of the arm is flat and has a hole |2| therein whereby the arm may be fastened in fixed relation to the plate H5 by means of a nut |23 as indicated in Fig. 3. A hooked portion |25, preferably of springy material, may be provided at the other end of the arm for frictional engagement with the edge of the plate H5 to hold the arm in place when the nut |23 is loosened for adjusting another arm.

A circular depression |21 is drilled in the arm H1, as indicated in the drawings, for receiving a ball bearing |29 which is mounted on a spring arm |3|. It will be clear from an inspection of Fig. 6 that as the ball |29 rides up the front face |33 of the arm |1, it is moved its maximum distance away from the plate H5, and moves towards the plate H5 again as the ball seats itself in the depression |21. When the ball |29 rides out of the depression |21, the arm |3| is not lifted as far away from the plate H5 as before since the back edge |35 of the depression is lower than its front edge |31.

The spring arm I3! carries a projection |39 on one end thereof for breaking the holding circuit at the desired instant. A spring switch arm 4.1 and a fixed contact point |4| (which may be identical with contact point 45, if preferred) are provided in the holding circuit as in Fig. 1, the switch arm 41 being so set with respect to the projection |39 that when the projection is moved away from the plate H5 the maximum amount, the projection slides past the end of the switch arm 41.

In operating the circuit shown in Fig. 3, the switch or key 25 at the remote point is closed for an instant and released, the switch being of the type which is normally open such as a telegraph key. This connects the motor 5 to the power supply 9 and closes the holding circuit for keeping the motor connected to the power supply until the spring switch arm 41 is moved away from the fixed contact point |4|. It will be assumed, for the purpose of explanation, that when the remote switch 25 was closed, the ball |29 was resting on the plate H5 at a point between two of the selector arms H1.

The motor rotates the plate l5 in the direction indicated by the arrow so that when the next selector arm H1 reaches the ball |29, the ball;

rides up the face |33 of the selector arm, forcing the projection |39 past the spring arm 41.

The motor continues to drive the plate H5 as the ball |29 starts to seat itself in the depression |21, but, before the ball is seated, the pro--l jection |39 breaks the holding circuit as it moves towards the plate H5 and moves the spring arm 41 away from the fixed contact point |4|. If the rotation of the parts due to inertia stops quickly enough, the spring arm 23| itself 11o-- tates the plate H5 a small distance further until the ball |29 is seated. Otherwise the spring arm 3| and ball |29 will act as a brake and rotate the plate H5 back to the proper position as explained in connection with Fig. l.

Just as in the circuit of Fig. 1, as the ball |29 seats itself in the depression |21, the projection |39 slides past the spring arm to the position illustrated, The desired station has now been selected and the circuit has been returned to its original condition.

Assume that it is desired to select the next station. The remote switch or key 25 is again closed momentarily. Again the motor turns the tuning condenser and plate H5. The ball |29 rides up out of the depression |21, passing over the back edge |35. The back edge |35 is so low, however, that the projection |39 does not slide past the spring arm 41 and, therefore the holding circuit remains closed.

As the plate H5 rotates, the ball |29 leaves the selector arm H1 and rides on the plate H5 until the next selector arm l1 is reached. Then the above-described operation is repeated to stop the rotor of the condenser l at the exact point required for receiving the next station.

It will be apparent that with the arrangement of Fig. 3, any desired station may be preset by tuning in the station manually, loosening a selector arm, moving it to the point where the ball seats in the selector arm depression and then tightening the selector arm. While only two selector arms have been illustrated, it will be understood that several more would be provided in practice.

As indicated in Fig. 6, the ball |25 and the depression |21 preferably have the same radius of curvature. Likewise, in Fig. 1, the ball 5l' and the depressions 53 preferably have the same radius of curvature. sions of the balls and the depressions is not essential, however, and in some cases it may be desirable to make the radius of curvature of a depression |21 or 53 greater than that of the cooperating ball bearing.

It should be understood that a projection of any suitable shape, such as one having a conical point, may be substituted for a ball bearing and that either the semispherical depression or any other suitable shape utilized in cooperation therewith.

In the apparatus shown in Fig. 3, the tuning condenser will tune over the entire frequency range twice in making one rotation unless precautions are taken to avoid such operation. As shown in Fig. 3, a short-circuiting switch |45, such as a piece of spring metal, may be mounted upon one of the insulating supporting members |41 of the stator frame, and so positioned that during a half rotation of the condenser it is in This relation between dimeni is provided with selecting arms |5| each of which comprises a metal strip having a hole in one end VVly to a stator plate or connected to it through source 9.

a resistor |59, whereby the tuning circuit is made inoperative for a half rotation of the condenser. Y Y

It is desirable to have a receiver so designed Ythat it is silent while tuning from one station-V to another.

I accomplish this by means of a switch |5|, shown in Figs. l and 3, which, when closed, completes the loud speaker circuit. When the relay il is open, the armature l5 is dropped down so that the switch V|5| is closed andthe loud speaker can be heard.

When key 25 is closed to tune in a different station, the armature 3 opens therswitoh |5| andthereby breaks the loud speaker circuit so that no sound issues from the loud speaker until the next stationV is tuned in. vIf preferred, a

switch may be arranged to short-circuit the loud speaker in response to the closing of relay Another embodiment of my invention is illustrated in Fig. "I where parts similar to those in Fig. 3 are indicated by like reference numerals.

In the apparatus shown in Fig. '1 the plate H5 Vfor fastening the arm at the center of the plate H5. The outer end of the arm 15| is in the form of a hook |53 for frictionally engaging the edge of the plate H5.

As indicated in Fig. 8, the end of each selector arm I5! Vis notched for cooperation with a wedgeshaped member |52 mounted on the end of a spring arm |54. Y

Also each selector arm i5| has a wedge-shaped contact'point |55 mounted'thereon for engagement with a spring switch armV |51.

TheV function ofthe Ycontact point |55 and switch arm 51 is to break the holding circuit of the relay il. This is accomplished by means of a relay |59 which consists of a solenoid winding |5| and an armature |65 pivoted at the point |55. So long as the armature 53 is in the position illustrated, the holding circuit is closed and the motor 5 is connected to the power As soon as the solenoid winding iti is energized, the armature |53 is moved and the holding circuit is broken, thereby disconnecting the motor from the power supply. Y Y

The wedge-shaped member |52 is pulled out of a selector armfnctchrwhen key 25 is closed, and held outbetween selector arms when the plate Y| l5 is rotated, by means of a solenoid |61 comprising a magnetic core |69 which is, mechanically connected to the spring arm i513, and two solenoid windings i1| and |13. The lower winding |1| is connected in the holding circuit while the upper winding |13 is connected in series with the through relay windings i9 and |13 to close relay ll and pull the wedge member |52 clear of the selector arm. At the same time the motor V5 is. started and the holding circuit is closed.

In the particular embodiment illustrated, the

lto the position shown in Fig. 8.

vaioaovo -holding circuit was closed the instant the relay |I 'closed because, in the Vcondition-initially assumed, the contact member |55 and switch arm |51 were out of contact as shown in Fig. 8 and,

consequently, the armature |53 of relay |59 was in the closed position illustrated.

The closing of theV holding circuit completedY a circuit through relay windings 31 and I1| whereby the motor is connected to thev power source 9 and the wedge-shaped member |52 is heldaway from the selector arms until the holding circuit is broken. Y Y

VThe holding circuit Vmay be traced from the left-hand terminal of source 9, through the winding 31, the conductor |15, the relay coil |1VI, the armature |63, and the conductor |11 to the right-hand terminal of source 9.V

The'motor will continue to run and rotate condenser and plate ||5 until the contact member |55 on the next selecting arm comes intoV the right-hand terminal of Asource S, through Y the conductor |11, the relay winding |6|, the

brush |19, the shaft 3, a selector 'arm |5|, a

contact point |55 andV switch arm |51, and

through a conductor |8| to the left-hand termi-V nal of source 9.

The instant the holding circuit is broken, Vthe relay from the power source and break the holding vcircuit at thecontact point di. Also, the spring arm |54 is released to seat the wedge-shaped member |52 in the notch in the selector arm and thereby position the rotor of condenser in the drops open to disconnect the motor :e

exact position required to receive the desired station. Y Y y As the member |52 seats itselfQit will rotate the plate -||5 forward (assuming the vino-tor stopped instantly) a 'slight' amount and the switch arm |51 will slide past the top of the contact member |55 and out of contact therewith If the overrun of the motor is too great, the spring will rotate the plate ||5 in the reverse direction a slight amount in the manner described in connection with Figs. 1 and 3.

As soon as switch arm |51 slides past contactY Y is open. The circuit is new in the condition originally assumed so that if the key'25'is again closed, the operation will be repeated to select the next station. Y

If desired, the armature |63 may be caused to function as a motor brake by mounting a brake drum |33 on the motor shaft in a position such that, when the armature |53 is pulled over to its open position, it makes contact with the brake drumv |83. If the motor armature has a small amount of inertia, it may be preferable to omit the brake drum |83. Again, it may be preferable to omit the spring |54 andrelay |61, relying upon the brake to prevent the motor from over running.

As in the circuit of Fig. 3, it Yis desirable to make the condenser ineffective for a rotationV of 180 degrees where the condenser is rotated continuously in one direction. For this purpose the g5 short-circuiting switch |45 and resistor |49 may be employed. As shown more clearly in Fig. 9, the switch |45 is preferably mounted upon an insulating member |85 and so positioned that it makes contact with a rotor plate during a half rotation thereof.

Instead of designing the apparatus so that the rotor of condenser rotates in one direction only, it may be preferred to add a reversing mechanism to the system shown in Fig. 7. The reversing mechanism shown in Fig. l, or one of any other suitable design may be used.

If a reversing mechanism is included in the circuit of Fig. 7, it is preferable that the adjustment of switch arm |51 be changed so that it makes contact with switch point |55 just an instant before the condenser rotor is in the desired position regardless of the direction of rotation of the selector arms. This action will take place if the switch arm |51 is set on a line drawn from the center of the plate ||5 to @le top or middle of the wedge-shaped member With the last-mentioned adjustment, the brake drum |83 may be utilized to prevent the motor from overrunning, or it may be omitted and the spring |54 relied upon to seat the member |52 and thereby bring the condenser rotor to the exact position desired. Also, with this adjustment the switch arm |51 remains in contact with the contact point |55 after the station has been selected.

It follows that when the key is again closed to select the next station, it must be held closed long enough to permit the contact point 55 to rotate away from switch arm |51. Otherwise the motor would not continue to run as the holding circuit would not be closed at the armature |63.

Obviously, the key 25 need not be held closed long, and, in fact, it must not be or the next station will be skipped instead of being tuned. in. If the key 25 is closed for a fraction of a second, that, in general, will be long enough.

The key 25 may be replaced by a special contact making device, such as a telephone dial of the type used with automatic telephone systems, for holding the circuit closed just long enough to permit contact |55 to rotate clear of arm |51, yet not long enough to allow a station to be skipped. It will be understood that only one electric impulse from the telephone dial would be utilized.

Figs. 10 and l1 illustrate a modified form of my invention in which the holding circuit is made ineffective by short-circuiting the Winding of the holding relay. In Fig. l0, only a portion of the remote control system is shown, the rest of the system being the same as that of Fig. l or Fig. 3.

Referring to Figs. 1G and ll it will be seen that in place of a single selector plate (as 5| in Fig. 1), a selector disc I9! is provided for each of the preselected stations. These selector discs are mounted on the shaft 3 to rotate with the tuning condenser. In order to simplify the drawings, only three selector discs have been shown.

A spring arm |55 and ball bearing |95 are provided for each selector disc |5| and so positioned that the ball |55 will seat in a depression |91 in the edge of a disc |9| when the condenser rotor reaches a preselected position.

A plurality of spring switch arms |99 and contact points 20| are connected in parallel across the winding 31 of the holding relay, the switch arms 19S normally being out of contact with the contact points 253i. Preferably, resistors .203 are connected in series with the contact points 25| to limit the flow of current when the coil 31 is short-circuited, the resistors having a lower impedance than that of the coil 31.

Each spring arm |93 is provided with a projection 255 which is adjusted to slide past the end of the switch arm |85 as the ball |95 seats itself in a depression, thus making contact between arm |95 and contact point 20| momentarily. This short-circuits the coil 31 and causes the relay to open and disconnect the motor from the power supply.

In order to make the short-circuiting of coil 31 more effective, a resistor 201 may be connected in series with coil 31. This will cause a substantial drop in voltage across coil 31 when a shunting circuit is closed.

It will be apparent that when key 25 is again closed, there will be no short across coil 31 and the motor will remain connected to the power source until the depression I 91 of another selector disc comes into position to actuate another switch arm |99.

Various modifications may be made in my invention without departing from the spirit and scope thereof, and I desire, therefore, that only such limitations shall be placed thereon as are necessitated by the prior art and set forth in the appended claims.

I claim as my invention:

l. In a remote control system for a radio receiver which includes a tuning element, a relay located at said receiver, means including a control device located at a point remote from said receiver for actuating said relay, means for changing the tuning position of said tuning element in response to the actuation of said relay, a holding circuit for said relay, means for closing said holding circuit in response to the actuation of said relay whereby the tuning position of said tuning element is continuously changed until said holding circuit is rendered ineifective, and means for making said holding circuit ineffective and for returning said control system to its original condition with respect to said control device in response to said tuning element reaching a predetermined tuning position whereby said tuning element is moved to a different position in response to a second actuation of said control device, said last means also including means for setting the tuning element at the exact predeter.- ined position after the holding circuit is made ineffective.

2. In a remote control system for a radio receiver which includes a tuning element, a relay located at said receiver, means including a control device located at a point remote from said receiver for actuating said relay, means for changing the tuning position of said tuning element in response to the actuation of said relay, a holding circuit for said relay, means for clos ing said holding circuit in response to the actuation of said relay whereby the tuning position of said tuning element is continuously changed until said holding circuit is rendered ineiective, means for making said holding circuit ineffective and. for returning said control system to its original condition with respect to said control device in response to said tuning element reaching a predetermined tuning position whereby said tuning element is moved to a different position in response to a second actuation of said control device, and additional means for setting the tuning element at the exact predetermined position after the holding circuit is made ineiective.

element of a radio receiver at a preselected position, said system comprising a motor mechanically connected to said element, a control circuit, means including a relay for connecting said motor to a source of power in response to the closing of said control circuit, means including a holding circuit for keeping said motor connected toY said source after said circuit has been opened,'and means responsive to the position of said element for making said holding circuit ineiective and vfor moving the said element to the exact preselected position after the holding circuit has been broken. Y

4. Ina control system for setting a radio tuning element at any one of a plurality of preselected positions, an electric motor mechanically connected to said element, a control circuit, means including a relay for connecting said motor to a source of power in response to the closing of said control circuit, means including a holding circuit for keeping. said motor connected to said source after said control circuit has been opened, and meansresponsiveV to the position Vof said tuning element for making said holding circuit Vineffective and for returning the connections of the control system to their original condition,V said last means including spring means for determining the position kof said tuning element after said holding circuit has beenmade ineiective..

5.V In a remote control system for setting aV Y radio'tuning element at any one oi a plurality of preselected stations, a source of power, an elec# tric motor mechanically coupled torsaid tuning element, a station selector plate mechanically coupled to said tuning element, a control device located at a point remote from said receiver, means including a relay located at YVsaid receiver for connecting said motor to said source of power in response to the actuation of saidr control de- Y vice, means for closing a holdingcircuit for said relay in response to the actuation of said relay, and means for breaking said holding circuit in Yresponse to said tuning element reaching a preselected position, saidlast means including contact points connected in series relation with said holding circuit, a spring arm carrying a member which rides on said plate between Vpreselected stations, said selector plate having an element at each preselected'position which has a depression therein, said spring arm being so positioned with respect to said selector plate that the said spring arm memberseats in one of said depressions when one4 of said preselected pcsitionsis reached, and means carried by said springarm and cooperating with one of said contact points to open said contact points momentarily as said member seats itself in said depression.VA

' 6. A remote control system according to claim 5 characterized in that said selector plate element comprises an arm supported by said selec? j tor plate and adjustable with respect thereto.

7. A remote control system according to claimV 5 characterized in that said selector plate element comprises an adjustable arm supported by said selector plate, the depression in said arm having a front edge which is higherjthan its back edge.

8. In aY tuning control system for a receiverV having ajtuning element therein, a primary driv-V 3. A remote control system for lsetting anY ing means coupled toY said tuning element for moving' it forward to a tuning position', a control device, means for energizing'said driving means in response to the actuation of said control device-whereby 'said element is moved forward toward a predetermined tuning position, an auxiliary driving means operating substantially independently of the inertia or" the moving Vparts of said primary driving means for moving said vtun-- ing element forward exactly to said predetermined position after said primary driving `means has moved said tuning element to the region of said predetermined position, and means for rendering said primary driving means ineffective and Vfor rendering said auxiliary driving means eiective to move said tuning element forward in response to said tuning element being moved to the region of said predetermined position. Y

9. In a tuning control system for a receiver Y having a rotatable tuning condenser therein, an

rotated toward a'predetermined tuning position,

means for maintaining a flow oi current to said motor until said condenser is Vrotated to the region or" said predetermined position, and means for interrupting said flow of current and for rotating said condenser to said exact predetermined position in response to said condenser reaching said region, said last means comprising a iirst cam member coupled to said condenser and a second cam member for engaging said iirst cam member, and also'comprising a spring for driving said cam members intoV engagement with sufficient force to rotate said condenser.

l0. The invention according to claim 9 characterized in that said first member is a rotatable element having a depression therein and `iurther characterized in that said second cam member is shaped to seat in said depression, said second cam member being so supported that it is forced against said rst cam member by said spring. Y

l1. In a tuning control system for a receiver having a tuning element therein, a primary driving means, means for coupling said driving means Vto said tuning element fork moving Vit to a tuning position, a control device, means Vfor' actly to said predetermined position after. saidv primary driving means has moved said element Vto the region oiY said predetermined position,

and means forrendering said primary driving Ymeans, ineiective and for rendering said auxiliary driving means effective to move said tuning eiementY in response VVto said tuning element being tion and beioreit reaches said position.

l2. 'in a receiver having a tuning element, a tuning control system for tuning said receiver to aV preselected station,.said system comprising a motor mechanically connectedto said element, means including a switch'for closing a power Y circuitV and thereby connecting said motor to a source of power in response tothe closing of said switch, means for holding said switchV closed Vmoved to the region of said predetermined posilll (itl

in response to the closing thereof, means for opening said power circuit in response to the tuning element reaching a predetermined position where the receiver is tuned only approximately to said station and thereby disconnecting said motor from said source or power and means operating substantially independently of the inertia of the moving parts of said system for next automatically tuning the receiver exactly to the predetermined station in response to said tuning element reaching said position.

18. In a remote control system for tuning a receiver to a preselected station, said receiver having a tuning element, a remote control switch which is normally open and which is located at a point remote from said receiver, a motor inechanically connected to said tuning element, means for connecting said motor to a source of power in response to a momentary closing oi said remote control switch, means for keeping said motor connected to said source of power after said remote control switch is opened, means for disconnecting said motor from said source of power in response to said tuning element being moved to a position where the receiver is tuned only approidmately to said preselected station, and means operating substantially independently of the inertia ci the moving parts of said system for tuning said receiver exactly to said station in response to said tuning element reaching said position.

14. In a control system for tuning a receiver to a preselected station, said receiver having a tuning element, a motor, means for coupling said motor to said tuning element, a control device, means for causing said motor to move said tuning element in response to the actuation of said control device, means for causing said motor to continue to move said tuning element until said tuning element is moved to a position where the receiver is tuned only approximately to said preselected station, and means operating substantially independently or" the inertia of the moving parts or" said system for causing said motor to cease moving said tuning element and for tuning said receiver exactly to said station in response to said tuning element reaching said position.

l5. In a tuning control system for a receiver having a tuning element therein, a primary tuning means comprising a motor, means ior coapling said motor to said tuning element for moving it to a tuning position, a control device, means for causing said motor to move said tuning element in response to the actuation of said control device whereby said element is moved towards a predetermined tuning position at which said receiver is tuned exactly to a preselected station, an auxiliary tuning means opn erating substantially independently oi the inertia oi moving parts in said system for tuning said receiver exactly to said preselected station after sriinary tuning means has moved said elernci to the region of said predetermined tuning po ion, and means for rendering said primary tuning means ineffective to move said element and for rendering said auxiliary tuning means effective automatically to tune said receiver exactly to said preselected stations in response to said tuning element being moved to the region of said prede ermined position and regardless of whether said primary tuning means stops moving said element before or after said element has reached said predetermined position.

16. In a receiver having a tuning element, a tuning control system for tuning said receiver to a preselected station, said system comprising a primary tuning means including a motor, means for coupling said motor to said tuning element for moving it to said preselected station, a preselecting element which is set to a position corresponding to said preselected station, a cooperating elernent, means for producing relative movement between said preselecting element and said cooperating element in response to movement of said tuning element, a control device, means for causing said motor to move said tuning element in response to the actuation of said control device whereby said tuning element is moved towards a position where said receiver is tuned exactly to said preselected station and whereby relative movement is produced between said preselecting element and said cooperating element, an auxiliary tuning means operating substantially independently of the inertia of moving parts in said system for tuning said receiver exactly to said preselected station after said primary tuning means has moved said element to the region of said position, and means for rendering said primary tuning means ineffective to move said element and for rendering said auxiliary tuning means effective to tune said receiver exactly to said preselected station in response to said preselecting element and said cooperating element moving into cooperating relation and regardless of whether said primary tuning means stops moving said element before or after said element has reached said predetermined position` i7. In a receiver having a tuning element, a tuning control system for tuning said receiver to any one of a plurality of preselected stations, said system comprising a motor, means for connecting said motor to said element, a plurality of preselecting elements which may be set to positions corresponding to said preselected sta tions, at least one cooperating element, means for producing relative movement between said preselecting elements and said cooperating element in response to movement of said tuning element, a control device, means for causing said motor to move said tuning element in response te the actuation of said control device whereby said tuning element is moved towards a position where said receiver is tuned exactly to one of said preselected stations and whereby relative movement is produced between said preselecting elements and said cooperating element, means for causing said motor to continue to move said tuning element until said tuning element is moved to the region of said position and until said cooperating element and one of said preseiecting elements move into cooperating relationship with each other, means for causing said motor to cease moving said tuning element in response to said cooperating element and said one preselecting element moving into cooperating relation, and means operating independently of the inertia of the moving parts of said system next automaticaily tuning said receiver exactly to said one preselected station in response to said cooperating element and said one preseiecting element reaching said cooperating position.

FLOYD M. HARRIS. 

